The semiconductor industry faces many challenges in the pursuit of device miniaturization including the rapid scaling of nanoscale features. Such challenges include the fabrication of complex devices, often using multiple lithography and etch steps. Furthermore, the semiconductor industry needs low cost alternatives to high cost EUV for patterning complex architectures. To maintain the cadence of device miniaturization and keep chip manufacturing costs down, selective deposition has shown promise. It has the potential to remove costly lithographic steps by simplifying integration schemes.
Selective deposition of materials can be accomplished in a variety of ways. For instance, some processes may have inherent selectivity to surfaces based on their surface chemistry. These processes are fairly rare and usually need to have surfaces with drastically different surface energies, such as metals and dielectrics.
In cases where surfaces are similar (SiO2 versus Si—H terminated or SiN) the surfaces may be selectively blocked by employing surface treatments that selectively react with one surface and not the other, effectively blocking any surface reactions during later ALD or CVD processes.
Self-Assembled Monolayer (SAM) is an approach to enable selective deposition on multiple material surfaces. Ideally, during the SAM passivation, SAM forms over all dielectrics surface perfectly, and block 100% metal oxide deposition from subsequent deposition steps so that metal oxide only grows on conductor/metal surface. However, the SAM monolayer grows in an asymptotic thickness as a function of deposition time and number of cycles so that achieving an ideal SAM that provides 100% blocking for the metal oxide is extremely difficult.
Additionally, excessive SAM precursor exposure on a densely packed SAM surface might lead to droplet defects. As a result, small amount of metal oxide might grow on SAM passivated surfaces, leaves many small metal oxide defects. Such metal oxide defects might impact subsequent SAM removal and mask removal processes.
Therefore, there is a need in the art for methods to remove defects formed as part of a SAM protected selective deposition process.